This invention relates to a structure for adding water to storage batteries in a safe manner whereby the liquid level is automatically controlled by the inner pressure within each battery and wherein the gases in each battery are isolated from adjacent batteries by water barriers.
In conventional batteries, adhesive materials and/or rubber packings have been used to tightly seal the water supply chambers. However, such seals are relatively complex in structure and difficult to produce, and they are often subject to small leakages which disrupts or disables the water fill function. Further, when a plurality of storage batteries are connected in series and/or parallel, as for an electric car or train installation, a great deal of time is required to sealingly connect each of the batteries and to add water thereto. Specifically, water pipes must be connected in the longitudinal and perpendicular directions of the battery array, and L or U-shaped pipes must be used to implement the perpendicular connections at the ends of the array. Further, the plurality of batteries commonly have high voltage and storage capacities, and since their interior spaces communicate with each other through the water pipe connections, if an explosion occurs in one cell due to inside or outside ignition by leakage current arcing or the like, all of the batteries may be sympathetically exploded, which creates a potential danger or hazard.
The gases generated in the respective batteries are exhausted to the atmosphere through a single discharge via an explosion preventing filter made of sintered aluminum or the like in order to prevent the batteries from exploding due to any flash ignitions in the atmosphere. However, if one cell explodes due to inside ignition, the explosion may easily propogate to all of the batteries. As an example, if a high voltage is applied to the relatively small area of a water connecting pipe, leakage current may flow therethrough if the inside of the pipe is damp due to surplus water remaining from a water fill operation or due to condensed acid moisture from the batteries during charging. If such dampness or moisture is discontinuous, arc ignition may occur and cause the batteries to simultaneously explode.